Altered lipoprotein composition and elevated serum lipids in chicken embryos with hereditary muscular dystrophy

The earliest biochemical changes reported in chickens with hereditary muscular dystrophy are increased cholesterol levels in liver, serum and pectoral muscles at 9 days of embryonic development. We have investigated whether there were concomitant differences in serum lipoprotein composition (VLDL, very low density lipoproteins; LDL, low density lipoproteins; HDL high density lipoproteins)**, and levels of serum triglycerides (TG), free cholesterol (FC) and cholesteryl esters (CE) in normal chicken embryos and in those with hereditary muscular dystrophy between 10 and 16 days in ovo. VLDL and CE content of the serum of dystrophic embryos are significantly elevated compared to those of the normal serum from 10 to 16 days in ovo, and serum TG is significantly increased at 12 and 14 days in ovo. Serum LDL and HDL concentrations are significantly lower in dystrophic embryos at 14, 16 and 12 days respectively. It is proposed that an increased rate of CE synthesis, probably in the liver, induces the formation of CE-rich, TG-poor VDLD-like lipoprotein. Decreased degradation of this lipoprotein by peripheral tissues, especially muscles, may account for the high VLDL levels in the dystrophic embryos. Since dystrophic chickens exhibit hyperlipoproteinemia followed by muscle degeneration, this disease has features in common with human spinal muscular atrophy.